It seems we didn’t reach 400PPM last week after all. The data has been revised. Ooops.
‘Carbon dioxide measurements in the Earth’s atmosphere did not break the symbolic milestone of 400 parts per million at a Hawaiian observatory last week, according to a revised reading from the nation’s climate observers.
The National Oceanic and Atmospheric Administration (NOAA) revised its May 9 reading at the Mauna Loa observatory in Hawaii, saying it remained fractions of a point below the level of 400 ppm, at 399.89′
Source: LA Times
Oh well, there’s always next week…or maybe not, since spring in the Northern Hemisphere tends to reduce CO2 as plants suck up all that CO2 that some claim is not plant food.
Still time to get t-shirts though.
H/t to Marc Morano